Flash arrester for draft intake of furnace fireboxes



Dec. 29, 1953 w. o. MORAN FLASH ARRESTER FOR DRAFT INTAKE OF FURNACE FIREBOXES 2 Sheets-Sheet 1 Original Filed Oct. 14, 1948 William afloran W. O. MORAN Dec. 29, 1953 FLASH ARRESTER FOR DRAFT INTAKE OF FURNACE FIREBOXES 2 Sheets-Sheet 2 Original Filed Oct. 14, 1948 swam 0'0 William 0.M0ran latented Dec. 2 9, 1953 FLASH ARRESTER FOR DRAFT INTAKE OF FURNACE FIREBOXES William 0. Moran, Tulsa, Okla.

Original application October 14, 1948, Serial No.

1952, Serial No. 297,617 b 3 Claims. (Cl. 126-85) This invention is directed to improvements in a flash arrester for the air intake of a furnace firebox and is a divisional application of my copending application Serial No. 54,451, filed c tober 14, 1948.

While the flash arrester, according to my invention, is not limited in this particular use, it is extremely well adapted for use on heaters or furnaces used in heating of meter houses and other like buildings associated with oil refineries, oil production fields, tank farms, and on pipe lines. Such heaters or furnaces used in c0nnection with heating pipe lines and meter houses are used where there is a distinct possibility of leakage of petroleum, particularly the more volatile fractions of petroleum, and the contamination of the atmosphere with vapors of such volatilized petroleum vapors as well as natural gases themselves. At times, the concentration of such vaporized and gaseous products in the atmosphere forms a mixture which is capable of ignition, even explosion, if subject to a flame or spark. Thus, it becomes imperative that the flame within the burner chamber or firebox of the furnace be held within the firebox and not allowed to communicate with the atmosphere adjacent the firebox at the draft intake thereof. Thus, I have provided a flash arrester which will prevent flame or spark from passing out of the firebox and into the surrounding atmosphere which might ignite a possible combustible atmosphere outside the firebox. Further, since the air intake of the heater or furnace is exposed to wind blowing from all directions and at different forces it is essential that the air intake to the furnace be baflled so that the full force of the wind does not directly impinge upon the flame in the firebox which might result in the extinguishment of the flame.

It is thus the primary object of my invention to provide an attachment for the air intake of a in which; i

Divided and this application July 8,

A further object of my invention is to provide a flash arrester which may be easily attached to the air intake of a furnace or boiler which incorporates a plurality of spaced fine-mesh screens to prevent flame from passing therethrough and includes baflies and hood for directing the air supply in such quantity and force that it will not extinguish the flame in the firebox of the heater or boiler to which the flash arrester is attached.

A still further object of the invention is to provide a flash arrester consisting of an elongated housing adapted for attachment at one end to the intake opening of a firebox on a heater or furnace while the other end is provided with a hood and bafile arrangement which permits intake air to enter through a circuitous path and the elongated housing has positioned adjacent the hood attached end and within the confines of the housing, a rigid shell with means for conecting the shell to the surrounding elongated housing so as to provide a tight closure therebetween with the rigid shell carrying transversely disposed and spaced apart fine-mesh screens which permit passage of air therethrough but prevent the passage of a flame.

Still further objects and the entire scope of applicability of the present invention will be-' oome apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examplesv are given by way of illustration only and, while indicating preferred embodiments of the invention, are not given by way of limitation, since various changes and; modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

For a more complete understanding of the invention reference may be had to the drawings Figure 1 is a cross section View of a meter house having a heater installed with a heater provided with a flash arrester;

Figure 2 is an elevational end view of the flash arrester as viewed from within the firebox end of the flash arrester;

Figure 3 is a cross sectional view as viewed along section lines 3-3 of Figure 2;

Figure 4 is a bottom view of the flash arrester as seen from section lines 4-4 in Figure 2;

Figure 5 is a cross sectional side elevation of a modified form of flash arrester having a conical shaped battle and a conical hood;

Figure 6 is an end view of the flash arrester shown in Figure 5 as viewed from the right-hand side thereof; and

Figure 7 is an end view showing the conical battle and the flash arrester as viewed along section line 11 in Figure 5.

Throughout the description and the various figures 'c' i drawings like reference numerals refer to similar parts.

In Figure 1 there is shown a meter house gen; erally indicated at having a safety heaterll projecting thru an end wall l0 thereof an fdis posed in a horizontal position with its" intake covered by a flash arrester [2 according to my in; vention and with an exhaust stackd'spo'd exterior of the meter house I'll as indicated at L3 The exhaust stack is provided wane-ma equalizing cap M on the top end thereof.

The flash arrester shown in Figures 2,3 and l is the flash arrester 52 as shown mounted on the heater I I in Figure 1 The modified form of flash arrester shown in Figures 5, 6 and 7' can equally as well be mounted on the a r intake end of t e heater u mstea'd'qr the hash arrster l2.

The flash arrester 1.2, as best shown n Figure 7 3 includes an elongatd housing lv which may be circular in shape depending dpoh the type 'of heater or furnace with which it used, and this elongated housing is a'dapted'to fitover the air intake end of thefir'ebox of the heater or i;

furnace. The elongated housing [5 has'it's rear end provided with a'trahsv'rsely extending flange |'6,se"e Fig. 3, which is apertured'throhghout its greater central portion 16" to pro'videfor entranc'eof airinto the elongatedhous'ing [5. This flange [6 also provides for mounting of other parts bf the flash arlfester an'din"order to mount these parts it has a'plu'r'al'ity or, di rcumferentially spaced apertures (6f? forre ceiyi ng the: through bolts] 1, "Mduntd' within the rear or air, intake.

end of housih'gli is a firstfina mesh screen I8 which extends "transversely an-tsetse cross sectionof the housi'ngls aii' at' its peripheral rear face abuts ag ns't'the ihsidbf sta ed." This screen [3 'is provided with a miiialit' bi spaced apertures IB about its pefipheral f ac' which are received ,over the. through bolts. 'l Mounted against the"othi' t iphera1rae of screen is and having the bolts ll passing through Suitably spaced apertures therein is an asbestoswasher' or ring {9 which has mounted thereagains't asecohd f ne-mesh screen2l1 in spaced relation to the first fine-mesh screen 18 and this second screen 20 is provided with a plurality of spaced apertures 20 about its peripheral portion so as to bereceive'dover and secured by the through bolts H. A rigidshell 21- of Y elongated cylindrical shape is received over the through bolts ll with its rear end riding against the secondfine-mesh screen 25. A third fine-meshjscreen 22,. having a plurality of spaced apertures]? soas tobe receivedover the through bolt I1 is mounted against theinner n p the ll ndis eeu e thereaeainst,by means of a circular ring orwasher 23 which also'providedwith a plurality of circumferentially. spaced apertures 23 soas to bereceived over the through bolts ll The whole assembly of rigid shell andfi'ne-mesh soreensand washers are held together by thev through bolts I T having take-up nuts H on the inner thereof.

On the rear end of the elongated housing I 5 or the other end from the furnace end mounting is mounted a hood generally indicated at 24 which has as its lower portion a semi-cylindrical skirt 25 fabricated from sheet metal as is the other housing 15 and shell 2| portions of the whole flash arrester. This semi-cylindrical skirt 25 is formed with a transversely extending flange 26 along its forward end and is provided with upstanding side portions 25 so as to provide for an air passage in alignment with the aperture IS in the central portion of the flanged end [B of elongated housing [5. The transversely extending end 26 and its portions 26' on either side are provided with apertures 21 in alignment with the through bolts thereadjacent as indicated at IT and 'II in Figure 3. Over the lower through Bolt 11-, as shown in Figure 3, is secured a baflie zil h a ving a flange 29 on the forward end thereof which extends downward at an acute angle and is aperturedfor mountin over the lower through bolt's'iil as shown. This bafiie 28 extends downwardly and rearwardly at an incline within the semi-cylindrical skirt 25 of hood 24 and at its rear end 28 is in spaced relation to the adjacent portion of skirt 25, as best shown in the bottom view in Figure 4.

In Figure 4 it will be noted that the baffle 28 is semicircular and the flange 29 thereof extends across as the diameter and is supported by the adjacent through bolts [1. It will be noted'that an arcuate moon-like shaped. aperture is formed between the rear edge 28' of the bafile 28 and the skirt portion 25 of housing 24 which aperture provides for the passage of air therethrough from the lower open 'end 25' of the hood 24, up into the skirted hood 25. and on into the opening 16 of elongated member I5.

Still referring to Figure 3 it will be noted that the upper portion of hoodv 24 is provided with an inclined roof section 29 attached to skirt portion 25. Roof portion '29 is formed with ahorizontally extending semi-circular lip portion 28 at the forward endthereof which projects a short distance over the reare'ndof the elongatedthousing I5 and forms an air passageway as indicated at 3B therebetween the elongated housing [5 and the lip 23'. The roof portion 29 is supported by bracket members 3| which have angula-rly bent end portions 3! andv 3|", 3| of which is, apertured and'received overone of the through bolts !.l,whi1e bent portions!" is apertured and has a bolt 32 passing therethrough' securing it to the roof 29 of hood, 24." Thus, there is provided by the hood 24 an air passageway at at the upper portion thereof which leads to the end opening [6 in housing l5 and one at the opposite portion at end 25. adjacent baflie 28 at the lower end of the hood 2i. No direct drafts of air can blow into the flash arrester, but the draft air must pass through circuitous passageways for entrance to the flame arrester. This construction provides for an even flow of draft air into the flame arrester and particularly throughthe spaced finemesh screens within the elongated housing 15. Draft air passes through these fine-mesh screens into the firebox 't'owhich this flame arrester is attached, however, flame from within the firebox will not pass back through these spaced finemesh screens andint'o the hood and out into the surrounding atmosphere. Thus, if this flame arrester is used on a heater or furnace within an atmosphere of combustible vapors, a safety feature is provided in that the flame in the furnace housin will not feed back through the: flame arrester since the spaced fine-mesh screens provide a barrier. While in some extreme cases a small portion of flame might pass through the third fine-mesh screen 22 adjacent the firebox, however, a spacing between the third screen 22 and the second screen an is such that the flame will not extend therebetween nor be able to feed back through the spaced first and second screens i8 and as as best shown in Figure 3.

The modified form of flame-arrester as shown in Figures 5, 6 and 7 will now be described. Referring to Figure 5, there is shown an elongated housing [5' which may be circular in shape dependent upon the furnace with which it is being used. Housing I5 is provided with inturned flanges it at its rear end which are apertured and received through bolts IT as in the fiame arrester shown in Figure 3. In the form of flame arrester shown in Figure 5 the first fine-mesh screen It is mounted adjacent the rear face of flange it instead of within the flange as shown in Figure 3 for the first described flame arrester. The second fine-mesh screen 20' is mounted adjacent the opposite face of flange i6 and is held tightly thereagainst by means of the rigid cylindrical shell 2! and the through bolts H. The third fine mesh screen 22' is mounted over the end of the rigid shell 2! and adjacent thereto and secured thereagainst by means of the circular ring or washer 23' by means of the through bolts i? and the take-up nuts 11.

Instead of the hood and baflie arrangement shown in Figures 2, 3 and 4, I provide for a conical shaped hood generally indicated at 40 which has an open end 4| and a lip portion 42 extending in spaced relationship about the rear end of the elongated housing l5 and thus there is formed an air receivin passageway 43 about the end It, as best shown in Figure 6. This conical shaped hood is is supported in spaced relationship on the rear end of housing l5 by means of brackets as which have their forward ends bent at right angles and apertured and received over through bolts H as indicated at 45 in Figure 5 while their rear ends are formed with an angle t6 and apertured to receive the through bolts ll which secure them to and support the conical shaped hood 4%. Four of these brackets 44 are shown equally spaced for supporting the hood as best shown in Figure 7.

In Figure 5 there is shown a, conical shaped apertured baflle 48 provided with a plurality of spaced apertures 49 in the wall thereof while the open end of the conical shaped bafiie is provided with a transverse outwardly extending flange 50 which is provided with a plurality of spaced apertures about its circumference for mounting over the through bolts 11 as best shown in Figure 5.

t will be noted that the hood 40 is mounted in spaced relationship about the conical aperture bafiie 48 and there is provided a passageway for air to be received between the hood 40 and the baffle 38 and passed through the apertures 49 of the baiile :38 on into the elongated housing l5 through the flash arresting screens 18', 20' and 22. As in the flash arrester described in Figure 3, air is permitted to pass into the flame arrester but the flame from within the firebox to which the flame arrester is attached is prevented from passing back through the flame arrester by means of the transversely extending spaced fine-mesh screen therein.

Since it is obvious that certain further changes can be made in the foregoing constructions without departing from the spirit and scope it is intended that all'matter shown in the accompanying drawings or described hereinbefore shall be interpreted as illustrative and not in .a limiting sense.

I claim as my invention:

1. A flame arrester for the air intake of a furnace firebox comprising, in combination, an elongated housing having one end thereof adapted to be connected with the air intake of a furnace firebox, a rigid shell disposed within said housing adjacent the other end thereof, means connecting said shell to said surrounding elongated housing providing a tight closure therebetween, a plurality of spaced apart fine-mesh screens disposed within said rigid shell and extending substantially transverse to the longitudinal axis of said elongated housing and the rigid shell therein and connected to said rigid shell for passage of supply air therethrough to the firebox but arresting a flame frome the firebox from passing back through said other end of the elongated housing, a hood attached to said elongated housing at the other end thereof, said hood being spaced from said other end of the elongated housing thereby providing air passageways about said other end of the elongated housing at opposite portions thereof which passageways are in communication with said other end of the elongated housing to permit the passage of supply air therethrough.

2. A flame arrester for attachment to the air intake of the firebox of a furnace comprising, in combination, a horizontally extending elongated casing having one end for attachment to the air intake of the furnace firebox, a plurality of finemesh screens disposed vertically across the interior of said casing and spaced each from the other, an end cover for the other end of said casing comprising a vertically extending semicylindrical enclosure for the lower portion of the other end of the elongated casing and an integral inclined roof closure attached to the upper end of the semi-cylindrical enclosure disposed over the remaining portion of said other end of the casing, said roof enclosure terminating in a lip spaced above and apart from said horizontal casing whereby a covered opening at said other end of the horizontal casing is provided to permit ingress of air therethrough and into the interior of said horizontal casing, said semi-cylindrical closure being open at its bottom end, and a bafile within said semi-cylindrical enclosure, said baffle being so shaped and proportioned as to provide a second air ingress passageway between its marginal edge and the interior of said semi-cylindrical enclosure.

3. A flame arrester for the air intake of a furnace firebox comprising, in combination, an elongated housing having one end thereof adapted to be connected with the air intake of a furnace firebox, a rigid shell disposed within said housing adjacent the other end thereof, means connecting said shell to said surrounding elongated housing providing a tight closure therebetween, a plurality of spaced apart fine-mesh screens disposed within said rigid shell and extending substantially transverse to the longitudinal axis of said elongated housing and the rigid shell therein and connected to said rigid shell for passage of supply air therethrough to the firebox but arresting a flame from'the fire box from passing back through said other end of the elongated housing, a conical baflle having a plurality of spaced apertures in the walls thereof attached at its base to and in communication with the other end of said 1 elongated houskzgandiconioathwd supporflngly attached to said-elongated *housing and Desitioned over and in spaced relation to uid-eonical battle with the base end thereof positioned 'in spaced relationship adjacent; the other end of said elongated :housing whereby :a. supply air passageway is provided leading from the space between the 'base end not thewafl of and "hand andtheadjacentrspaced other end of saidelongated housing to the space: between saidvconical hood and ,said conical apertured gbafile spaced within said hood.

,MORAN.

References Cited in the file of this patent UNITED s A Es PATENTS Number Name Date 5 1,237,858 Ballinger Aug. 21, 1917 1 ,641,011 Sargent Aug. 30, 1927 3,196,828 Hess v Apr. 9, 1940 2,531,139 Lilly-eh a1. Nov. 21 1950 FOREIGN PATENTS Number Country Date 573,356 Germany Mar. 30, 1933 

